// Copyright [2020] <unknown>
#include <bits/stdc++.h>
using namespace std;
// #define ONLINE_JUDGE
#ifndef ONLINE_JUDGE
#define dbg(x...) { cerr << "\033[32;1m" << #x << " -> "; err(x); }
void err() { cerr << "\033[39;0m" << endl; }
template<typename T, typename... A>
void err(T a, A... x) { cerr << a << ' '; err(x...); }
#else
#define dbg(...)
#endif

#define sz(x) ((int)x.size())

typedef long long LL;

const int N = 1e5+50;

int t, n, r;

int a[N], x[N];

int main(int argc, char const *argv[]) {

    scanf("%d", &t);
    for (int kk=0; kk<t; ++kk) {
        scanf("%d%d", &n, &r);
        for (int i=0; i<n; ++i) {
            scanf("%d", &a[i]);
        }
        sort(a, a+n);
        n = unique(a, a+n) - a;
        LL dx = 0;
        int ans = 0;
        for (int i=n-1; i>=0; --i) {
            if (a[i] - dx <= 0)
                continue;
            else {
                dx += r;
                ++ans;
            }
        }
        cout << ans << endl;

    }
    // code
    return 0;
}
